If you go to your Dashboard>Appearance>Editor, on the right side of the editor page you will see the header named Templates. Under the Templates heading you will see all of the templates that are part of the theme. Scroll down to the template named sidebar and click on it. You will now see that code in the editor. By reading the code you can decipher which sections that you need to delete to remove the content. You can play around with it until you get it to look the way you want it to.
